In some fields the degree is critical; if you don't have it no one will even talk to you since there are lots of other folks with degrees. Or the education gained with the degree is absolutely necessary (like an MD)
In other fields, it just doesn't matter. It might help you get in the door, but once you have a few years of experience under your belt, no one really cares.
And if you run your own business... well, fire yourself if you don't have a degree!
I've got 15 years of experience in my field. Nobody cares if I have a degree or not at this point. Skills, experience, hard work, and reputation are key. In my field, reputation is critical. If you are a screw up, word gets around and mysteriously you don't get the jobs you thought you should have gotten. It's a small world, and everyone knows everyone else. Keep your nose clean, do honest hard work, be a team player, and people will want to work with you.